High-sensitivity galvanometer positioning precision measuring method

Abstract

The invention relates to the technical field of galvanometer positioning, in particular to a high-sensitivity galvanometer positioning precision measuring method, which adopts a micro-displacement measuring system to be combined with a laser and a diaphragm to measure the galvanometer positioning precision. The emergent light of the laser device enters the galvanometer after passing through the diaphragm, and then enters the micro-displacement measurement system through the field lens of the galvanometer, and finally, the micro-displacement measurement system performs micro-displacement measurement, so that the positioning accuracy is judged. According to the invention, the equipment cost can be greatly reduced while high-precision measurement is realized.

Description

Technical Field

[0001] The invention relates to the technical field of galvanometer positioning, and in particular to a high-sensitivity galvanometer positioning accuracy measurement method. Background Art

[0002] Galvanometers are widely used in laser processing. The positioning accuracy of galvanometers directly affects the accuracy of laser processing. Therefore, various indicators of galvanometers must be measured before leaving the factory. Among them, repeatability, static jitter, zero-position temperature drift, and gain temperature drift are particularly critical. But in the final analysis, these indicators are all manifestations of the positioning accuracy of galvanometers. How to accurately measure the positioning accuracy of galvanometers is a key technology in the research and development and production of galvanometers.

[0003] The difficulty in measuring the positioning accuracy of a galvanometer is that the galvanometer itself has an extremely high accuracy, which is higher than the accuracy of most commercial angle measuring instruments. For example, the repeatability of positioning accuracy and static jitter (i.e., position fluctuations caused by various interferences and noises when stationary) can reach 1μrad or even less, and the long-term drift and temperature drift of a high-precision galvanometer are usually only 30μrad. The basic principle of measurement is that the accuracy and resolution of the measuring instrument must be at least one order of magnitude higher than the measured indicator, while the measurement resolution and accuracy of angle measuring instruments commonly used to measure the positioning accuracy of galvanometers (such as photoelectric autocollimators) are both above 5μrad, which is difficult to meet the measurement requirements.

[0004] Existing measurement methods all use photoelectric autocollimators for measurement, which has the following disadvantages:

[0005] 1) The high-precision autocollimator costs tens of thousands or even hundreds of thousands of yuan, which is unaffordable for most companies. Therefore, at present, the mass-produced galvanometers can only be inspected by random sampling, which cannot completely eliminate the quality risks of the products leaving the factory;

[0006] 2) The angular resolution and accuracy of the autocollimator are not sufficient to meet the measurement requirements, and the measurement results are not convincing enough;

[0007] 3) Due to optical considerations, when using an autocollimator to measure temperature drift, the galvanometer is usually not equipped with a field mirror (the target mirror of the autocollimator must be a plane mirror because the galvanometer is required to remove the scene before measuring the positioning accuracy). Therefore, there are obvious deficiencies in the measurement results, and it is impossible to rule out the influence of the field mirror on the accuracy of the galvanometer. Summary of the invention

[0008] The present invention provides a high-sensitivity galvanometer positioning accuracy measurement method, which can achieve high-precision measurement while significantly reducing equipment costs.

[0009] According to a high-sensitivity galvanometer positioning accuracy measurement method of the present invention, a micro-displacement measurement system is used in combination with a laser and an aperture to measure the galvanometer positioning accuracy; the laser's emitted light passes through the aperture and is incident on the galvanometer, and is emitted to the micro-displacement measurement system through the galvanometer's field lens, and finally the micro-displacement measurement system performs micro-displacement measurement to determine the positioning accuracy.

[0010] Preferably, the micro-displacement measurement system uses a cylindrical reflector to reflect incident light onto a photoelectric position detector.

[0011] Preferably, the micro-displacement measurement system uses an Invar housing that is free of thermal expansion.

[0012] Preferably, the micro-displacement measurement system includes a one-dimensional micro-displacement measurement system, a two-dimensional micro-displacement measurement system based on a split light path, and a two-dimensional micro-displacement measurement system based on a standard ball and a two-dimensional photoelectric position sensor.

[0013] Preferably, the one-dimensional micro-displacement measurement system includes a cylindrical reflector, a filter, a one-dimensional photoelectric position detector and an Invar housing. After the laser emitted through the galvanometer enters the one-dimensional micro-displacement measurement system, the stray natural light is filtered out by the filter and then incident on the one-dimensional photoelectric position detector through the cylindrical reflector.

[0014] Preferably, the two-dimensional micro-displacement measurement system based on the splitting path includes a filter, a splitting prism, a reflector, two cylindrical reflectors, two one-dimensional photoelectric position detectors and an Invar housing. After the laser emitted by the galvanometer enters the two-dimensional micro-displacement measurement system, the filter filters out stray natural light, and then the beam is divided into two by the splitting prism, one of which is directly incident on the cylindrical reflector and, after reflection, is incident on the one-dimensional photoelectric position detector in the X direction, and the other beam passes through the reflector and the cylindrical reflector in sequence and is incident on the one-dimensional photoelectric position detector in the Y direction, thereby realizing micro-displacement measurement in both the X and Y directions.

[0015] Preferably, a two-dimensional micro-displacement measurement system based on a standard sphere and a two-dimensional photoelectric position sensor includes a filter, a standard sphere, a two-dimensional photoelectric position detector and an Invar housing. After the laser emitted through the galvanometer enters the two-dimensional micro-displacement measurement system, the filter filters out stray natural light, and then reflects it through the standard sphere to the two-dimensional photoelectric position detector, thereby realizing micro-displacement measurement in both XY directions.

[0016] The present invention provides a simple method to measure the positioning accuracy of the galvanometer, which greatly reduces the equipment cost while achieving high-precision measurement. The core purpose is to widely promote the method of the present invention in the mass production of galvanometers and improve the quality of galvanometer products. The present invention adopts a simple optical structure to realize a variety of micro-displacement measurement systems suitable for different scenarios, can intuitively measure the position of the light spot at the end of the galvanometer, avoid the use of expensive autocollimators, facilitate mass production, and greatly reduce the overall cost of galvanometer positioning accuracy measurement equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a principle diagram for measuring the positioning accuracy of a high-sensitivity galvanometer;

[0018] Figure 2 This is the schematic diagram of the one-dimensional micro-displacement measurement system;

[0019] Figure 3 The schematic diagram of the two-dimensional micro-displacement measurement system based on the split-beam path;

[0020] Figure 4 This is the schematic diagram of the two-dimensional micro-displacement measurement system based on a standard ball and a two-dimensional photoelectric position sensor.

[0021] The following are marked in the figure:

[0022] 1: galvanometer, 2: micro displacement measurement system, 3: laser, 4: aperture, 201: cylindrical reflector, 202: filter, 203: invar housing, 204: one-dimensional photoelectric position detector, 301: beam splitter prism, 302: reflector, 401: standard sphere, 402: two-dimensional photoelectric position detector. DETAILED DESCRIPTION

[0023] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the embodiments are only for explaining the present invention and are not intended to limit it.

[0024] Example

[0025] This embodiment provides a high-sensitivity galvanometer positioning accuracy measurement method, such as Figure 1 As shown, a micro-displacement measurement system 2 is used in combination with a laser 3 and an aperture 4 to measure the positioning accuracy of the galvanometer 1; the emitted light of the laser 3 is incident on the galvanometer 1 after passing through the aperture 4, and is emitted to the micro-displacement measurement system 2 through the field lens of the galvanometer 1, and finally the micro-displacement measurement system 2 performs micro-displacement measurement to determine the positioning accuracy.

[0026] The micro-displacement measurement system 2 uses a cylindrical reflector 201 to reflect the incident light onto the photoelectric position detector, which can amplify the tiny displacement of the light beam by dozens of times and achieve high-sensitivity micro-displacement detection.

[0027] The micro-displacement measurement system 2 uses an Invar housing 203 without thermal expansion, which can ensure that the measurement system itself has no temperature drift.

[0028] The micro displacement measurement system includes a one-dimensional micro displacement measurement system, a two-dimensional micro displacement measurement system based on a split light path, and a two-dimensional micro displacement measurement system based on a standard ball and a two-dimensional photoelectric position sensor.

[0029] The one-dimensional micro-displacement measurement system includes a cylindrical reflector 201, a filter 202, a one-dimensional photoelectric position detector 204 and an Invar housing 203. After the laser emitted by the galvanometer 1 enters the one-dimensional micro-displacement measurement system, the stray natural light is filtered out by the filter 202, and then is incident on the one-dimensional photoelectric position detector 204 through the cylindrical reflector 201.

[0030] The principle of one-dimensional micro displacement measurement system is as follows Figure 2 As shown, the light beam first passes through the filter 202 to filter out natural light and stray light, and then is reflected by the cylindrical reflector 201 to the one-dimensional photoelectric position detector 204. The tiny displacement of the incident light in the horizontal direction will be magnified by the cylindrical reflector 201 by dozens of times, which greatly increases the sensitivity of the measurement system. The magnification is proportional to L. According to the optical principle, given the radius R of the cylindrical reflector 201 and the distance L between the one-dimensional photoelectric position detector 204 and the reflection point of the incident light, it can be deduced that the incident light offset e will cause the light spot on the photoelectric position detector to move h. The relationship between h and e is:

[0031]

[0032] also, Figure 2 The entire measuring system is enclosed in an Invar housing 203 that does not expand when heated, thereby ensuring the thermal stability of the micro-displacement measuring system itself and improving the reliability of the measuring results.

[0033] Figure 2 The one-dimensional micro displacement measurement system can only detect micro displacement in one direction. In order to achieve two-dimensional measurement, this embodiment proposes Figure 3 and Figure 4 Two 2D micro-displacement measurement systems, Figure 3 The demonstration is based on the principle of splitting the light path. Figure 4 The demonstration is based on the principle of a calibration sphere and a two-dimensional photoelectric position detector.

[0034] like Figure 3As shown, the two-dimensional micro-displacement measurement system based on the split light path includes a filter 202, a splitter prism 301, a reflector 302, two cylindrical reflectors 201, two one-dimensional photoelectric position detectors 204 and an invar housing 203. After the laser emitted by the galvanometer 1 enters the two-dimensional micro-displacement measurement system, the filter 202 filters out stray natural light, and then the beam is split into two by the splitter prism 301, one of which is directly incident on the cylindrical reflector 201 and is incident on the one-dimensional photoelectric position detector 204 in the X direction after reflection, and the other beam passes through the reflector 302 and the cylindrical reflector 201 in sequence and is incident on the one-dimensional photoelectric position detector 204 in the Y direction, thereby realizing micro-displacement measurement in the XY directions. By adjusting the positions of various optical components, the optical paths of the two cylindrical reflectors 201 to the filter 202 are equal, and the distances between the two one-dimensional photoelectric position detectors 204 and the cylindrical reflectors 201 are equal, so that the same sensitivity in XY can be achieved, which facilitates direct measurement of temperature drift in two directions.

[0035] like Figure 4 As shown, the two-dimensional micro-displacement measurement system based on the standard ball and the two-dimensional photoelectric position sensor includes a filter 202, a standard ball 401, a two-dimensional photoelectric position detector 402 and an invar housing 203. After the laser emitted by the galvanometer 1 enters the two-dimensional micro-displacement measurement system, the stray natural light is filtered out by the filter 202, and then reflected by the standard ball to the two-dimensional photoelectric position detector 402, so as to realize the micro-displacement measurement in the XY direction. The system can realize the micro-displacement measurement in two directions at the same time, and has a simple structure, but has the disadvantage of different sensitivity in the two directions, and needs to be calibrated before use.

[0036] The present invention and its embodiments are described schematically above, and the description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and designs a structural method and an embodiment similar to the technical solution without creativity without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. A high-sensitivity galvanometer positioning accuracy measurement method, characterized in that: A micro-displacement measurement system is used in combination with a laser and an aperture to measure the positioning accuracy of the galvanometer. The laser's emitted light passes through the aperture and enters the galvanometer, and is emitted to the micro-displacement measurement system through the galvanometer's field lens. Finally, the micro-displacement measurement system performs micro-displacement measurement to determine the positioning accuracy.

2. A high-sensitivity galvanometer positioning accuracy measurement method according to claim 1, characterized in that: The micro-displacement measurement system uses a cylindrical reflector to reflect the incident light onto the photoelectric position detector.

3. A high-sensitivity galvanometer positioning accuracy measurement method according to claim 2, characterized in that: The micro-displacement measurement system uses an Invar housing that does not experience thermal expansion.

4. A high-sensitivity galvanometer positioning accuracy measurement method according to claim 3, characterized in that: The micro displacement measurement system includes a one-dimensional micro displacement measurement system, a two-dimensional micro displacement measurement system based on a split light path, and a two-dimensional micro displacement measurement system based on a standard ball and a two-dimensional photoelectric position sensor.

5. A high-sensitivity galvanometer positioning accuracy measurement method according to claim 4, characterized in that: The one-dimensional micro-displacement measurement system includes a cylindrical reflector, a filter, a one-dimensional photoelectric position detector and an Invar shell. After the laser emitted by the galvanometer enters the one-dimensional micro-displacement measurement system, the stray natural light is filtered out by the filter and then incident on the one-dimensional photoelectric position detector through the cylindrical reflector.

6. A high-sensitivity galvanometer positioning accuracy measurement method according to claim 4, characterized in that: The two-dimensional micro-displacement measurement system based on the splitting path includes a filter, a splitting prism, a reflector, two cylindrical reflectors, two one-dimensional photoelectric position detectors and an Invar housing. After the laser emitted by the galvanometer enters the two-dimensional micro-displacement measurement system, the filter filters out the stray natural light, and then the beam is split into two by the splitting prism, one of which is directly incident on the cylindrical reflector and, after reflection, is incident on the one-dimensional photoelectric position detector in the X direction, and the other beam passes through the reflector and the cylindrical reflector in turn and is incident on the one-dimensional photoelectric position detector in the Y direction, thereby realizing micro-displacement measurement in both the X and Y directions.

7. A high-sensitivity galvanometer positioning accuracy measurement method according to claim 4, characterized in that: The two-dimensional micro-displacement measurement system based on the standard ball and the two-dimensional photoelectric position sensor includes a filter, a standard ball, a two-dimensional photoelectric position detector and an Invar shell. After the laser emitted by the galvanometer enters the two-dimensional micro-displacement measurement system, the stray natural light is filtered out by the filter, and then reflected by the standard ball to the two-dimensional photoelectric position detector to realize micro-displacement measurement in the XY directions.

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